Also known as urticaria, hives are itchy, raised and swollen red bumps (weals) that appear on your skin. They can pop up anywhere on your body, including your ears, face, lips, throat and tongue. They vary in size from a few millimetres to the size of a dinner plate. Several weals can merge together to form larger patches called plaques. They may go away in a few hours or last for a few weeks.
Hives are a reaction to histamine, a chemical released by your body as part of the immune response.
They’re more common in children, women aged 30-60 and anyone who’s susceptible to allergies.
Hives are classed as either:
You may have:
Hives are usually harmless but sometimes they can be the first symptom of anaphylaxis, a potentially life-threatening allergic reaction. Other symptoms of anaphylaxis include:
You may also have an increased heart rate. Call 999 if you think you or someone else has anaphylaxis.
Hives will probably go away in 48 hours. However, if your hives persist after this time, you should see your GP.
You should also see your GP if:
You should also see your GP if you’re concerned about your child’s hives.
Your GP will examine your rash and ask about any other symptoms to help determine what’s causing it. They may ask you further questions about your symptoms such as:
They may also ask questions about your family history, lifestyle and recent experiences, such as:
Your GP may ask you to keep a diary to track:
If your GP suspects your hives are caused by an underlying condition, they may arrange further investigations, such as blood tests or skin tests.
Tests are often not necessary but sometimes your GP may refer you to an allergy clinic.
You may be referred for the following tests:
Hives occur when blood plasma leaks out of blood vessels in your skin. This happens in response to histamine released by cells along these blood vessels. Certain triggers cause histamine and other chemicals to build up causing hives.
In many cases, it isn't possible to discover what triggered hives. However, the most common cause of hives is an allergy. Common allergy triggers include:
Non-allergy triggers include:
Chronic hives last more than six weeks and in most cases, the cause remains unknown. However, in some cases it may be caused by:
You may find that these triggers make hives worse or come back:
You may not need any treatment because hives often clear up in a couple of days. In the meantime, it’s best if you avoid any triggers you know you have.
Treatments include a short course of corticosteroids, which suppress your immune system, menthol cream to soothe itching and/or antihistamines.
Antihistamines block the effects of histamine, the chemical that causes the weals and itching. However, they may not be suitable for young children or if you have a long-term medical condition, so speak to your pharmacist before trying them.
Non-drowsy antihistamines are usually recommended as they do not have many side effects. If the initial dose prescribed isn't effective, your doctor may increase the dose. If non-drowsy antihistamines aren't effective, your doctor may suggest other antihistamines, which can make you drowsy and should be taken at bedtime.
If antihistamines are not effective, your doctor may prescribe:
If you have chronic hives your doctor may also refer you to a dermatologist, a doctor specialising in skin conditions. They may suggest stronger antihistamines or other medicines to suppress your immune system, such as ciclosporin and omalizumab.
Chronic hives can last for months or years and disturb your sleep, as well as interfere with work and other activities. You can ease your symptoms or help prevent your hives recurring by avoiding:
It can also help to: